Traditionally, small animals and pets have been supplied with water through use of an open top bowl for containing the water or an open end drinking tube affixed to a bottle container with a resilient closure. Both these methods of water supply delivery have attendant problems of drippage, leakage, environmental debris, and unavoidable back flow of contamination. Open bowls may be jostled and their contents spilled out.
It is clear that traditional methods of watering small animals usually resulted in providing more water to the animal than the animal needed for its particular drinking use.
In the prior art, livestock waterers have been disclosed which were primarily directed to a method for keeping the water supply warm during freezing cold temperatures; see P. Paulsen, U.S. Pat. No. 1,326,778. Limited access water supplies have been disclosed in U.S. Pat. No. 4,559,905 to Ahrens and U.S. Pat. No. 3,771,496 to Atchley. In the Ahrens patent, a buoyant spherical float was used as a valve to allow access by livestock to the watering tank only when the animal pushed down on the buoyant float. No particular discrete limit as to the amount of liquid was provided. Atchley discloses the use of a movable control ball at the end of a long tube connected to an inverted bottle water supply for use by hamsters and the like. Again, there is no particular control of the quantity of water supplied when a small animal demands delivery.